Content creators and providers, such as movie studios, production companies and service providers (ISPs), have a need for protecting their investment, for example, movies, programming, services, software, and the like. Such content has typically found its way to the consumer through terrestrial broadcasts, premium programming, cable or satellite channels, pay-per-view events, and retail sales and rentals of videocassettes.
In terrestrial broadcasts, program content is transmitted in digital format to an access device such as a digital receiver. The nature of digital storage and transmission allows endless generations of copies to be produced with the same quality as the original master. Furthermore, unless the signal is encrypted, the received content may be easily copied and/or forwarded to additional products or devices not intended or authorized to receive such content. Moreover, products with digital outputs allow for the convenience of networked systems and higher quality recording and re-transmission of data. A home network, which receives content for display and storage, must now also protect content against illegal copying or distribution.
It has been proposed that a broadcast flag (BF) be carried in a digital signal such as a video broadcast stream, for the purpose of identifying that the digitally encoded data (such as video content) shall not be transmitted outside of the receiving device's own network. As used herein, the term content includes the digital signal, or the digitally encoded data, that is used to carry the program content. The flag may be carried in the PMT/EIT field of an MPEG-2 transport stream, for example, as a field comprising one or more bits. Currently, however, no mechanism exists for implementing how a network such as a home network should honor the flag so that content is not transmitted outside of the network.
One possible solution is to add additional flags into other portions of the digital signal, such as an Ethernet header, to signify to a router, cable modem and the like, that the content should not be forwarded to the outside world. Another proposal would require the use of only protected (encrypted data) interfaces such as IEEE 1394 with SC or DVI with HDCP. However, such implementations have the disadvantage of requiring costly changes to the infrastructure of existing (as well as future) home networks. Such infrastructure changes would significantly impede the trend of customers using their home network to distribute content to other electronic devices within their own home, thereby stifling a very promising market for home user electronic devices and content distribution within a home network.